Donald P. Frush, M.D.
Division Of Pediatric Radiology, Duke University Medical Center
 

Background 

-         CT is an invaluable modality: individual benefits far outweigh costs/risks.

-         There are risks; radiation is one.

-         There are unique issues with respect to radiation and CT in children.

-         CT is the greatest medical dose:

•   CT accounts for only about 5% of imaging procedures using radiation;

•   However, CT accounts for 40-60% of all medical radiation making it the largest source of medical radiation.

-         The use of CT is increasing (approximately 600% increase from 1980 to mid 1990’s).

-         Technology is becoming more complex with increasing challenges for appropriate pediatric CT technique. 
 

CT Radiation in Children: Unique Issues 

-         Children’s organs are more radiosensitive than in adults for an equivalent amount of radiation

-         Children have longer lifetime to manifest radiation related changes (i.e. cancer)

-         Technical parameters for CT should be adjusted based on:

1.      child size

2.      the region scanned (i.e. chest vs abdomen)

3.      indication

-         Adjustments are infrequently made: children often scanned with adult exposure factors (eg adult chest CT mAs 240, pediatric chest mA should be 20 –120mAs, depending on size). Radiation dose proportional to mAs 1:1: eg 2x mAs= 2x dose

-         Part of the lack of adjustments are due to lack to pediatric guidelines

-         Part of lack of adjustments are due to the increased complexity of scanning: literally, there are hundreds of possibilities for an individual scan, not all appropriate in terms of radiation dose
 

What Are the Radiation Risks in Children? 

-         Currently, general consensus is that even low radiation exposures do not have a “threshold” for radiation-induced cancers.  That is, there is no amount of radiation which should be considered absolutely safe.

-         While an individual CT or collection of scans have never been proven to cause cancer (this relationship may take up to 50 years to determine), new data suggest that the thresholds for cancer development from low dose radiation exposure and CT doses which can occur during clinical scanning have the potential to overlap.

-         For example, one recent investigation suggested that a single relatively high dose CT examination in a child increases the risk of cancer by 0.35% over background rate (Brenner, et al AJR February 2001).

Solutions: 

-         The responsibility of minimizing radiation lies with clinicians, radiologists and radiology personnel, industry, and various medical and governmental organizations.

-         Only perform necessary CT exams: communication with primary care and subspecialty providers is critical in this respect in minimizing radiation.

-         Consider other modalities (i.e., sonography and MR imaging).

-         Radiologists should limit examination to area of question, and adjust examination based on patient size, region scanned, and scan indication.

-         Support research and to investigate issues with radiation, CT, and CT radiation related cancer.

-         Establish information resources: currently, the Society for Pediatric Radiology (SPR) is developing a resource network which will provide primary care providers, radiologists, and other individuals information related to radiation and CT in children.

-         Because of all these points, pediatric radiologists have changed the way that all radiologists (i.e. adult imagers) have approached radiation and CT.

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Last Updated:
Thursday, 21 August, 2003